1. Field of the Invention
This invention relates to a transmission module with a circuit element and a control element mounted on a circuit board, and a circuit board used therein.
2. Description of the Related Art
In recent years, for a transmission module with a microprocessor having a built-in memory mounted on a circuit board, a firmware has been downloaded into the memory built in the microprocessor prior to factory shipment. The circuit board of the transmission module is provided with a pad for firmware downloading, separately from a card edge connector to be connected to a host, from the point of view of size reduction, cost reduction, etc. A probe is brought into contact with that pad, and the firmware is downloaded via this probe. Also, when the circuit board is mounted with an optical element, work such as alignment and adjustment to the amount of light is needed before factory shipment.
Also, there is a conventional transmission module, which, in order to perform unit verification as to whether or not a microprocessor with a built-in memory is operated as intended, measures voltage of a pad via a probe, compares the measured voltage and an intended voltage, and thereby verifies the operation of the microprocessor (Refer to e.g. JP-A-2007-303859).
Also, conventionally, a circuit board has been suggested that is provided with a card edge connector at opposite ends of a substrate body and that is mounted with electronic components thereon (Refer to e.g. JP-A-2013-171985).